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      <a id="urandom"></a>
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      <a id="IndexUrandom" class="indexterm"></a>
      <div class="refnamediv">
        <h2>
          <span class="refentrytitle">urandom</span>
        </h2>
        <p>urandom — 
      truly random opcodes with controllable range.
          </p>
      </div>
      <div class="refsect1">
        <a id="idp160268512"></a>
        <h2>Description</h2>
        <p>
      truly random opcodes with controllable range. These
      units are for Linux only and use /dev/urandom to construct
      Csound random values
    </p>
      </div>
      <div class="refsect1">
        <a id="idp160269984"></a>
        <h2>Syntax</h2>
        <pre class="synopsis">ax <span class="command"><strong>urandom</strong></span> [imin, imax]</pre>
        <pre class="synopsis">ix <span class="command"><strong>urandom</strong></span> [imin, imax]</pre>
        <pre class="synopsis">kx <span class="command"><strong>urandom</strong></span> [imin, imax]</pre>
      </div>
      <div class="refsect1">
        <a id="idp160275008"></a>
        <h2>Initialization</h2>
        <p>
      <span class="emphasis"><em>ix</em></span> -- i-rate output value.
    </p>
        <p>
      <span class="emphasis"><em>imin</em></span> -- minimum value of range; defaults to -1.
    </p>
        <p>
      <span class="emphasis"><em>imax</em></span> -- maximum value of range; defaults to +1.
    </p>
        <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
          <table border="0" summary="Note: Notes">
            <tr>
              <td rowspan="2" align="center" valign="top" width="25">
                <img alt="[Note]" src="images/note.png" />
              </td>
              <th align="left">Notes</th>
            </tr>
            <tr>
              <td align="left" valign="top">
                <p>
        The algorithm produces 2^64 different possible values which
        are scaled to fit the range requested.  The randomness comes
        form the usual Linux /dev/urandom method, and there is no
        guarantee that it will be truly random, but there is a good
        chance.  It does not show any cycles.
      </p>
              </td>
            </tr>
          </table>
        </div>
      </div>
      <div class="refsect1">
        <a id="idp160280448"></a>
        <h2>Performance</h2>
        <p>
      <span class="emphasis"><em>ax</em></span> -- a-rate output value.
    </p>
        <p>
      <span class="emphasis"><em>kx</em></span> -- k-rate output value.
    </p>
      </div>
      <div class="refsect1">
        <a id="idp160283008"></a>
        <h2>Examples</h2>
        <p>
      Here is an example of the urandom opcode at a-rate. It uses the file <a class="ulink" href="examples/urandom.csd" target="_top"><em class="citetitle">urandom.csd</em></a>.

      </p>
        <div class="example">
          <a id="idp160284880"></a>
          <p class="title">
            <strong>Example 958. An example of the urandom opcode at a-rate.</strong>
          </p>
          <div class="example-contents">
            <p>See the sections <a class="link" href="UsingRealTime.html" title="Real-Time Audio"><em class="citetitle">Real-time Audio</em></a> and <a class="link" href="CommandFlags.html" title="Csound command line"><em class="citetitle">Command Line Flags</em></a> for more information on using command line flags.</p>
            <pre class="programlisting">
<span class="csdtag">&lt;CsoundSynthesizer&gt;</span>
<span class="csdtag">&lt;CsOptions&gt;</span>
<span class="comment">; Select audio/midi flags here according to platform</span>
<span class="comment">; Audio out   Audio in</span>
-odac           -iadc    <span class="comment">;;;RT audio I/O</span>
<span class="comment">; For Non-realtime ouput leave only the line below:</span>
<span class="comment">; -o rnd31.wav -W ;;; for file output any platform</span>
<span class="csdtag">&lt;/CsOptions&gt;</span>
<span class="csdtag">&lt;CsInstruments&gt;</span>

<span class="comment">; Initialize the global variables.</span>
<span class="ohdr">sr</span> <span class="op">=</span> 44100
<span class="ohdr">kr</span> <span class="op">=</span> 4410
<span class="ohdr">ksmps</span> <span class="op">=</span> 10
<span class="ohdr">nchnls</span> <span class="op">=</span> 1

<span class="comment">; Instrument #1.</span>
<span class="oblock">instr</span> 1
  <span class="comment">; Create random numbers at a-rate in the range -2 to 2</span>
  aur urandom  <span class="op">-</span>2, 2

  <span class="comment">; Use the random numbers to choose a frequency.</span>
  afreq <span class="op">=</span> aur <span class="op">*</span> 500 <span class="op">+</span> 100

  a1 <span class="opc">oscil</span> 30000, afreq, 1
  <span class="opc">out</span> a1
<span class="oblock">endin</span>


<span class="csdtag">&lt;/CsInstruments&gt;</span>
<span class="csdtag">&lt;CsScore&gt;</span>

<span class="comment">; Table #1, a sine wave.</span>
<span class="stamnt">f</span> 1 0 16384 10 1

<span class="comment">; Play Instrument #1 for one second.</span>
<span class="stamnt">i</span> 1 0 1
<span class="stamnt">e</span>


<span class="csdtag">&lt;/CsScore&gt;</span>
<span class="csdtag">&lt;/CsoundSynthesizer&gt;</span>
</pre>
          </div>
        </div>
        <p><br class="example-break" />
    </p>
        <p>
      Here is an example of the urandom opcode at k-rate. It uses the file <a class="ulink" href="examples/urandom_krate.csd" target="_top"><em class="citetitle">urandom_krate.csd</em></a>.

      </p>
        <div class="example">
          <a id="idp160290240"></a>
          <p class="title">
            <strong>Example 959. An example of the urandom opcode at k-rate.</strong>
          </p>
          <div class="example-contents">
            <pre class="programlisting">
<span class="csdtag">&lt;CsoundSynthesizer&gt;</span>
<span class="csdtag">&lt;CsOptions&gt;</span>
<span class="comment">; Select audio/midi flags here according to platform</span>
<span class="comment">; Audio out   Audio in</span>
-odac           -iadc    <span class="comment">;;;RT audio I/O</span>
<span class="comment">; For Non-realtime ouput leave only the line below:</span>
<span class="comment">; -o rnd31_krate.wav -W ;;; for file output any platform</span>
<span class="csdtag">&lt;/CsOptions&gt;</span>
<span class="csdtag">&lt;CsInstruments&gt;</span>

<span class="comment">; Initialize the global variables.</span>
<span class="ohdr">sr</span> <span class="op">=</span> 44100
<span class="ohdr">kr</span> <span class="op">=</span> 4410
<span class="ohdr">ksmps</span> <span class="op">=</span> 10
<span class="ohdr">nchnls</span> <span class="op">=</span> 1

<span class="comment">; Instrument #1.</span>
<span class="oblock">instr</span> 1
  <span class="comment">; Create random numbers at k-rate in the range -1 to 1 </span>
  <span class="comment">; with a uniform distribution.</span>
  k1 urandom
        
  <span class="opc">printks</span> "k1<span class="op">=</span><span class="op">%</span>f\\n", 0.1, k1
<span class="oblock">endin</span>


<span class="csdtag">&lt;/CsInstruments&gt;</span>
<span class="csdtag">&lt;CsScore&gt;</span>

<span class="comment">; Play Instrument #1 for one second.</span>
<span class="stamnt">i</span> 1 0 1
<span class="stamnt">e</span>


<span class="csdtag">&lt;/CsScore&gt;</span>
<span class="csdtag">&lt;/CsoundSynthesizer&gt;</span>
</pre>
          </div>
        </div>
        <p><br class="example-break" />

      Its output should include lines like this:
      </p>
        <pre class="screen">
k1=0.229850
k1=-0.077047
k1=-0.199339
k1=-0.620577
k1=-0.119447
k1=-0.596258
k1=0.525800
k1=-0.171583
k1=-0.017196
k1=-0.974613
k1=-0.036276
      </pre>
        <p>
    </p>
      </div>
      <div class="refsect1">
        <a id="idp160293168"></a>
        <h2>Credits</h2>
        <p>Author: John ffitch</p>
        <p>New in version 5.13</p>
      </div>
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